From the FDA Drug Label
The use of Phenazopyridine HCl is contraindicated in patients with renal insufficiency. The FDA drug label does not answer the question of what GFR is considered renal insufficiency, but based on the information provided, Phenazopyridine HCl is contraindicated in patients with renal insufficiency.
- A GFR of 46 indicates impaired renal function, which may be considered renal insufficiency.
- Therefore, Pyridium 100mg tid x 2 days is not recommended for a patient with a GFR of 46 1.
From the Research
Phenazopyridine (Pyridium) should be used with caution in patients with impaired renal function, and the proposed dose of 100mg tid x 2 days may need to be adjusted for a patient with a GFR of 46. Given the patient's GFR of 46, which indicates mild to moderate renal impairment, dose reduction may be necessary to minimize the risk of toxicity 2, 3. The standard dose of Pyridium is 200 mg three times daily for no more than two days when used with antibiotics for urinary tract infections. However, in patients with mild to moderate renal impairment, a dose reduction to 100 mg tid may be considered, but the treatment duration should be limited to minimize the risk of complications such as methemoglobinemia, hemolytic anemia, and yellow-orange discoloration of body fluids 4, 5. It is essential to monitor the patient's renal function and adjust the dose accordingly to avoid further renal impairment. Alternative urinary analgesics or pain management strategies should be considered for patients with significant renal dysfunction who need relief from urinary symptoms 6. In this case, considering the patient's GFR of 46, it is recommended to use the lowest effective dose of Pyridium for the shortest duration possible, and to closely monitor the patient's renal function and for signs of toxicity.